Kvass is a traditional fermented Slavic and Baltic beverage commonly made from rye bread, which is known in many Central and Eastern European and Asian countries as "black bread". The color of the bread used contributes to the color of the resulting drink. Kvass is classified as a "non-alcoholic" drink by Ukrainian, Belarusian, Russian, Latvian, Lithuanian, Polish, Hungarian, Serbian, and Romanian standards as the alcohol content from fermentation is typically low (0.5–1.0% or 1–2 proof).